The suspended balls swing back and forth at slightly different rates, determined by the length of the strings. Each ball completes a set number of swings in 30 seconds, from the longest (15 swings in 30 seconds) to the shortest (24 swings in 30 seconds). Set in motion together, the balls go in and out of several interesting patterns before they line up again after 30 seconds.
Welcome to an occasional series devoted to "cool stuff" that I encounter while browsing the world of mathematics and computer science. I'll peek at new developments in math and its applications, and I'll revisit old puzzles, famous problems, and historic events—anything mathematical that happens to catch my eye. I hope you'll find something of value in these brief, informal forays into the world of math.
Ivars Peterson is a freelance writer and editor. He was Director of Publications at the Mathematical Association of America from 2007 to 2014. As an award-winning mathematics writer, he previously worked at Science News for more than 25 years and served as editor of Science News Online and Science News for Kids. His books include The Mathematical Tourist, Islands of Truth, Newton's Clock, and Fragments of Infinity: A Kaleidoscope of Math and Art.